HVAC dampers often include a series of damper blades that can pivot to various degrees of opening to regulate air flowing through the damper. The drive mechanism for pivoting the damper blades often comprises a complicated assembly of bearings, couplings, drive shafts, and linkages. The various drive components can be difficult to assemble, and often the components themselves extend into the airflow path, which can create an undesirable flow obstruction.
Some dampers have a frame made of sheet metal, which inherently has relatively thin, sharp edges. Such edges can make it difficult to radially support the shaft of a damper blade without the sheet metal edges cutting into the shaft.
Consequently, there is a need for a multi-blade damper that has a minimum number of parts, is easy to assemble, and provides little or no obstruction to air flowing through the damper.